From: frank_...@hotmail.com   
      
   Hey All,   
      
   I just got a "The Cricket!" sound/speech/clock peripheral for my //c. It   
   didn't come with a power supply, but I was hoping to reverse engineer one. The   
   specs are 5.5x2.5mm center positive 9 volts BUT the clock section relies on a   
   120hz pulse in the DC to    
   advance the clock. Pulses above 9 volts are converted to a square wave that's   
   fed to pin 39 of the on-board microcontroller. Presumably it uses an interrupt   
   on that chip to advance the clock timer.   
      
   I had the unit open, and was able to upload some specs and pictures to Asimov.   
   I also took the liberty to replace the electrolytic capacitors while the unit   
   was open, as several had drifted.   
      
   Would anyone happen to have an otiginal power supply that's been opened? Or be   
   able to point me towards a circuit which would work? I'm guessing 12vac   
   transformer into a full-wave rectifier with a 12v zener to provide the clock   
   signal which is then fed    
   back into the filtered 9v output. The PS output seems to swing between 9v and   
   11v at 120 hz.   
      
   Frank   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)